The present invention relates generally to bearing assemblies, and particularly to self-aligning clutch release bearing assemblies in automobile friction disc clutches.
A common problem in typical automobile friction disc clutches arises from a misalignment or eccentricity between the engine crankshaft or clutch input shaft axis and the transmission shaft axis. With clutch release bearings having a fixed axis of rotation, this eccentricity subjects the clutch release bearing to chafing and vibration when engaged by the clutch release levers to actuate, i.e. disengage, the clutch. It has been common for the release bearing to be engaged only during clutch actuation by the vehicle operator. However, in some applications it has been found desirable to have the bearing engaged continuously and hence to be lightly or more forcefully engaged with the clutch release levers depending upon whether the clutch is actuated or not. In this situation the problems of chafing, etc., due to eccentricity are even more aggravated since the rotatable race member of the clutch release bearing will be in continuous rotating engagement with the clutch release levers whenever the engine is running.
The present invention provides a novel clutch release bearing assembly which is self-aligning and has special utility with the constantly engaged clutch bearing design. With prior self-aligning bearings, some type of retaining spring or mechanical retaining structure is used to hold the bearing in the aligned position when the clutch is engaged. In the present invention, no such device is used, and if the bearing were disengaged from the clutch release levers, it would move out of the aligned position. The present invention, however, converts the otherwise undesirable effects of the constantly engaged clutch bearing design into a valuable asset for aligning and maintaining alignment of the clutch release bearing with the input shaft axis of the clutch without the need for a retaining spring or mechanical structure. Accordingly, it is an object of the present invention to provide a self-aligning clutch release bearing for use with a constantly engaged clutch bearing design, which is of simple design, durable in operation, and which is of economical manufacture. With prior self-aligning bearing assemblies, the retaining spring inhibits rotation of the bearing assembly. In the present invention, where a retaining spring is not utilized, a simple sleeve with an interlocking tab and slot structure is used to prevent rotation and at the same time to provide a means for holding the components of the self-aligning bearing assembly in an assembled relationship. Thus, it is another object of the present invention to provide a novel self-aligning bearing assembly having a unique anti-rotation construction.
In accordance with the present invention, a resilient retainer sleeve is interposed between the bearing and a tubular bearing carrier, and the bearing is constructed to provide a predetermined annular radial clearance between an inner race member of the bearing and the retainer sleeve. The retainer sleeve serves to hold the bearing in an assembled relationship with the bearing carrier, as well as to prevent the rotation of the inner race member with respect to the bearing carrier. The predetermined radial clearance permits the bearing to shift radially with respect to the bearing carrier, such that the bearing axis can be aligned with the input shaft axis. This radial shifting movement occurs automatically since the radial chafing force exerted by the rotating clutch release levers will force the bearing to shift radially and assume the axis of the input (flywheel) of the clutch. It will be appreciated that a number of transient forces may act upon the bearing assembly to cause temporary misalignments. Accordingly, the alignment of the bearing axis with the clutch input axis will typically not be static, but rather dynamic in character. However, as long as the clutch release levers are rotating, the constant engagement of these levers with the bearing will continuously provide the force required to dynamically maintain the bearing in alignment with the clutch input axis. Another advantage of the resilient retainer member is that it serves to reduce noise which may result from the radial shifting movement of the bearing with respect to the bearing carrier.
Additional features and advantages of the invention will become apparent in view of the drawings and the following detailed description of the preferred embodiment.